Stratigraphy and Facies Analysis of the Lokoja Formation, Kogi State

The Lokoja Formation, exposed prominently along the Niger-Benue Trough confluence area in Kogi State, North Central Nigeria, represents a significant Lower Cretaceous fluvial to deltaic succession with implications for understanding early basin development and sediment provenance in central Nigeria. This study presents a stratigraphic and facies analysis of the Lokoja Formation in selected outcrops around Lokoja town, evaluating vertical lithological changes, sedimentary structures, and depositional environments. Detailed measured sections were constructed at three key exposure localities, recording bed thickness, grain size trends, sedimentary structures such as cross-bedding, parallel lamination, and scour surfaces, and lateral facies relationships. Grain size analysis was conducted using sieving and pipette methods to characterise the textural maturity of the sandstone intervals. Sedimentary log correlation panels were constructed to assess lateral continuity of key lithological units. The palaeoenvironmental interpretation integrates facies associations with published regional studies on early Cretaceous sedimentation in the Benue Trough. Detrital zircon geochronology literature is reviewed to contextualise provenance interpretations. The study contributes a documented and digitised stratigraphic record for the Lokoja Formation, filling gaps in the regional mapping effort. Undergraduate students gain foundational skills in stratigraphic logging, facies analysis, and palaeoenvironmental reconstruction applicable across Nigerian sedimentary basins. Keywords: stratigraphy, Lokoja Formation, facies analysis, Cretaceous, Kogi State.